• Title/Summary/Keyword: Natural emission

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An Investigation on the Emission Characteristics of Heavy-duty Vehicles using CNG and Diesel Fuel According to the Various Driving Cycles (다양한 주행모드에 따른 천연가스(CNG) 및 경유 사용 대형자동차의 배출가스 특성에 관한 연구)

  • Kim, Hyungjun;Eom, Myungdo;Kim, Jeongsoo
    • Transactions of the Korean hydrogen and new energy society
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    • v.23 no.6
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    • pp.634-639
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    • 2012
  • The contribution levels of emissions from the heavy-duty vehicles have been continuously increased. Among the exhaust emissions, NOx (nitric oxides) have a ratio of 73.2% and particle matters have a proportion of 61.8% in the heavy-duty vehicles. Also, natural gas vehicles have the 78.9% of total registered local buses in Korea. Therefore, the investigation on emission characteristics of heavy-duty vehicles using CNG and diesel fuel according to the various driving cycles was carried out in this study. In order to analyze the emission characteristics, the five kinds of buses by using CNG and diesel fuels with a after-treatment devices (DPF, p-DPF) was used and five test driving schedules were applied for analysis of emission characteristics in a chassis dynamometer. To analyze the exhaust emission, the exhaust emission and PM analyzers were used. From this study, it is revealed that diesel buses with after-treatment had reduced emission of CO, HC, PM but NOx. Also, NMHC emission of CNG bus have a higher level and NOx level was similar with diesel buses. In addition, emissions in NIER06 with slow average speed shows lowest levels compared to other test modes.

Development of Vehicle Emission Model with a High Resolution in Time and Space (${\cdot}$공간적 고해상도 자동차 배출량 모형의 개발)

  • Park, Seong-Kyu;Kim, Shin-Do;Park, Ki-Hark
    • Journal of Environmental Health Sciences
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    • v.30 no.3
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    • pp.293-299
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    • 2004
  • Traffic represents one of the largest sources of primary air pollutants in urban area. As a consequence, numerous abatement strategies are being pursued to decrease the ambient concentration of pollutants. A characteristics of most of the these strategies is a requirement for accurate data on both the quantity and spatial distribution of emissions to air in the form of an atmospheric emission inventory database. In the case of traffic pollution, such an inventory must be compiled using activity statistics and emission factors for vehicle types. The majority of inventories are compiled using passive data from either surveys or transportation models and by their very nature tend to be out-of-date by the time they are compiled. The study of current trends is towards integrating urban traffic control systems and assessments of the environmental effects of motor vehicles. In this study, a model of vehicle emission calculation by using real-time traffic data was studied. Traffic data, which are required on a street-by-street basis, is obtained from induction loops of traffic control system. It is possible that characteristics of hourly air pollutants emission rates is obtained from hourly traffic volume and speed. An emission rates model is allocated with a high resolution space by using geographic information system (GIS). Vehicle emission model was developed with a high resolution spatial, gridded and hourly emission rates.

An Experimental Study on Performance and the Exhaust Emissions in a Small High Speed Gas Engine by Using Natural Gas and Hydrogen Fuel (천연가스 및 수소연료를 사용하는 소형 고속 가스엔진에 있어서 성능 및 배기 특성)

  • Kim B.S.;Shioji M.;Chu B. G.
    • Journal of the Korean Institute of Gas
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    • v.4 no.2 s.10
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    • pp.20-26
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    • 2000
  • In this experimental study, we examined gas engine characteristics of a small high-speed engine in various ways. And we studied performance of natural gas, hydrogen gas and gasoline fuel engines, as emission characteristics and process of combustion. For the purpose of preventing back-fire occurred in case of high-speed and high load in hydrogen engine, we controlled air quantity by installing throttle valve in gas fuel engine. We performed experiment by mixing nitrogen to hydrogen fuel. As a result, we could find out characteristics which of a high speed small engine by applying gas fuels.

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Effect of Ganglioside $G_{M3}$ on the Erythrocyte Glucose Transporter (GLUT1): Conformational Changes Measured by Steady-State and Time-Resolved Fluorescence Spectroscopy

  • Yoon, Hae-Jung;Lee, Min-Yung;Jhon, GiI-Ja
    • BMB Reports
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    • v.30 no.4
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    • pp.240-245
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    • 1997
  • Interactions between ganglioside $G_{M3}$ and glucose transporter, GLUT1 were studied by measuring the effect of $G_{M3}$ on steady-state and time-resolved fluorescence of purified GLUT1 in synthetic lipids and on the 3-O-methylglucose uptake by human erythrocytes. The intrinsic tryptophan fluorescence showed a GLUT 1 emission maximum of 335 nm, and increased in the presence of $G_{M3}$ by 12% without shifting the emission maximum, The fluorescence lifetimes of intrinsic tryptophan on GLUT1 consisted of a long component of 7.8 ns and a short component of 2,3 ns and $G_{M3}$ increased both lifetime components. Lifetime components were quenched by acrylamide and KI. Acrylarnide-mduced quenching of long-lifetime components was partly recovered by $G_{M3}$ However. KI-induccd quenching of short- and long-lifetime components was not rescued by $G_{M3}$. The anisotropy of 1.6-diphenyl-1.3.5-hexatriene (DPH)-probed dimyristoylphosphatidylcholine (DMPC) model membrane was also increased with $G_{M3}$ incorporation, The transport rate of 3-O-methylglucose increased by 20% with $G_{M3}$ incorporation on the erythrocytes, Therefore, $G_{M3}$ altered the environment of lipid membrane and induced the conformational change of GLUT1.

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Exhaust and Combustion Characteristics of Premixed Swirl Burner for Steam Reforming System (선회류 예혼합버너를 적용한 개질기용 연소시스템의 배기 및 연소특성)

  • Cha, Chun Loon;Hwang, Sang Soon
    • Journal of the Korean Society of Combustion
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    • v.19 no.3
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    • pp.34-43
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    • 2014
  • The reformer system is a method for hydrogen production from hydrocarbon fuels such as natural gas under high temperature environment($about{\sim}1,000^{\circ}C$). The premixed swirl burner with mixing swirler and combustion swirler designed to deliver fuel cell electric output from 0.5 kW to 1.5 kW. Premixed swirl burner experiments using natural gas and mixture of natural gas and anode off gas were carried out to analyse flame patterns and stability by equivalence ratio respectively. The results show that the stable swirl flame can be established for all cases of fuels type using the premixed swirl burner. The swirl flame had a wide stability region and it showed very low CO(50 ppm) and $NO_x$(20 ppm) emission at different fuel type and various equivalence ratio conditions. The operating range of premixed swirl burner for stable swirl flame is found to exist between equivalence ratio of 0.70 to 0.90 for turn down ratio of 3:1.

Development of Gasoline Engine Renewal CNG Generator and a Study on Exhaust Gas Characteristics of Equivalent Diesel Engine (가솔린 엔진개조 CNG 발전기 개발과 동급 디젤엔진의 배출가스 특성 연구)

  • Lee, Jung-Cheon;Kim, Ki-Ho;Lee, Jung-Min;Park, An-Young
    • Journal of Power System Engineering
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    • v.22 no.6
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    • pp.74-79
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    • 2018
  • Compressed natural gas has a high octane number and low particulate emission characteristics as compared with petroleum-based fuels, so it can respond to exhaust gas regulations positively. A natural gas engine has been introduced to improve the quality of the atmosphere, a diversity of fuel, a stable supply, and it has widely been used in city buses and garbage trucks. Recently, the natural gas engine has received attention by overcoming the disadvantage of the theoretical air-fuel ratio method through the development of EGR cooler and engine parts with the development of LP-EGR technology. In this study, we try to develop the cogeneration system that can simultaneously generate electric power and heat by remodeling the gasoline engine to the mixer type CNG engine. As a result, it was able to reduce the NOx (approximately 77%) compared to the diesel engines with same displacement.

Physical Properties of Molecular Clouds in NGC 6822 Hubble V

  • Lee, Hye-In;Pak, Soojong;Oh, Heeyoung;Le, Huynh Anh N.;Lee, Sungho;Lim, Beomdu;Tatematsu, Ken'ichi;Park, Sangwook;Mace, Gregory;Jaffe, Daniel T.
    • The Bulletin of The Korean Astronomical Society
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    • v.44 no.1
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    • pp.66.4-66.4
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    • 2019
  • NGC 6822 is a dwarf irregular galaxy whose metal abundance is lower than of the Large Magellanic Cloud. Hubble V is the brightest HII complex where molecular clouds surround the core cluster of OB stars. Because of its proximity (d = 500 kpc), we can resolve the star-forming regions on parsec scales (1 arcsec = 2.4 pc). Using the high-resolution (R = 45,000) near-infrared spectrograph, IGRINS, we observed molecular hydrogen emission lines from photo-dissociation regions (PDRs) and $Br{\gamma}$ emission line from ionized regions. In this presentation, we compare our data PDR models in order to derive the density distribution of the molecular clouds on parsec scales and to estimate the total mass of the clouds.

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Acid Stability of Anti-Helicobacter pyroli IgY in in Aqueous Polyol Solution

  • Lee, Kyong-Ae;Chang, Sung-Keun;Lee, Yoon-Jin;Lee, Jong-Hwa;Koo, Nan-Sook
    • BMB Reports
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    • v.35 no.5
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    • pp.488-493
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    • 2002
  • IgY was separated from a hen's egg yolk that was immunized with Helicobacter pyroli. The anti-H. pyroli IgY activity at acidic pH and the suppressive effect of polyol on acid-induced inactivation of IgY were investigated. Sorbitol and xylitol were used as polyols. IgY was quite stable at pH 5~7. Irreversible inactivation of IgY was observed at pH below 4, and proceeded rapidly at pH below 3. The acid stability of IgY was enhanced in the presence of 30% sorbitol or above. In a 50% aqueous sorbitol solution, an acid-induced inactivation was almost completely suppressed at pH 3. However, the improvement of IgY activity was not observed in the aqueous xylitol solution. IgY showed almost the same activity as native IgY when sucrose was substituted for sorbitol. On the other hand, the xylitol replacement with sucrose did not enhance the acid stability of IgY. The acid-induced inactivation of IgY was related to tryptophyl fluorescence. Fluorescence emission spectra suggested that structural changes near the tryptophan residues may occur under acidic conditions. An increase in sorbitol concentration induced a blue shift. The fluorescence emission of IgY in a 50% sorbitol solution had a peak at 330 nm, which was the same emission peak that was exhibited by native IgY. Sorbitol could, therefore, be used as a good stabilizer of IgY under acidic conditions.

Optimal Optical Filters of Fluorescence Excitation and Emission for Poultry Fecal Detection

  • Kim, Tae-Min;Lee, Hoon-Soo;Kim, Moon-S.;Lee, Wang-Hee;Cho, Byoung-Kwan
    • Journal of Biosystems Engineering
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    • v.37 no.4
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    • pp.265-270
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    • 2012
  • Purpose: An analytic method to design excitation and emission filters of a multispectral fluorescence imaging system is proposed and was demonstrated in an application to poultry fecal inspection Methods: A mathematical model of a multispectral imaging system is proposed and its system parameters, such as excitation and emission filters, were optimally determined by linear discriminant analysis (LDA). An alternating scheme was proposed for numerical implementation. Fluorescence characteristics of organic materials and feces of poultry carcasses are analyzed by LDA to design the optimal excitation and emission filters for poultry fecal inspection. Results: The most appropriate excitation filter was UV-A (about 360 nm) and blue light source (about 460 nm) and band-pass filter was 660-670 nm. The classification accuracy and false positive are 98.4% and 2.5%, respectively. Conclusions: The proposed method is applicable to other agricultural products which are distinguishable by their spectral properties.

Study on Analysis of Heat Dissipation due to Shape of Motorcycle Disc Brake (모터사이클 디스크 브레이크 형상에 따른 방열해석에 관한 연구)

  • Cho, Jae-Ung;Han, Moon-Sik
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.12 no.4
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    • pp.100-107
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    • 2013
  • This study aims to improve the heat performance of motor cycle disk due to the number of holes by analyzing 6 kinds of disk models. This disk performance depends on the efficiency at emitting the heat. To raise the efficiency of heat emission, holes with circle or another configuration are made on disks to emit heat fast. The distribution of temperature, heat flux, deformation and stress are analyzed. As the number of holes on disk increases, the performance of heat emission is improved. Equivalent stress is decreased and durability is improved as the number of holes on disk increases. Though the number of holes on disk is increased, the performances of heat emission and durability do not become better. The optimal model can be found by comparing models each other through this analysis result. Through this study result, the configuration of motor cycle disk is designed with optimal heat emission and durability by comparing models.